TECH
26
NOTE
The code is valid for 60 minutes. If the user fails to register on the website within this
time, a new code must be generated.
Internet module parameters such as IP address, IP mask, gate address etc may be set manually
or by selecting DHCP option.
VI.a)
Factory settings
This function enables the user to restore factory settings saved by the manufacturer.
VII.
Protections
In order to ensure safe and failure-free operation, the regulator has been equipped with a range
of safeguards. In case of alarm, a sound signal is activated and the display shows an appropriate
message.
In order for the controller to return to the operation mode, press MENU. In the case of ‘CH
temperature too high’ alarm, it is necessary to wait until the temperature drops below the alarm
value.
VII.a)
Thermal protection of CH boiler
The controller is equipped with a bimetallic mini-sensor (placed next to CH boiler temperature
sensor), which automatically disconnects the fan from the power supply when the alarm
temperature of 90°C is exceeded. It prevents the water in the installation from boiling in case of
CH boiler overheating or controller damage. After this protection has been activated and the
temperature has dropped to a safe level, the sensor automatically unlocks itself. In the case when
this sensor is damaged or overheated, the fan is also disconnected.
In the case of CH boiler protection in a closed system, a STB type temperature limiter is
used instead of a bimetallic mini-sensor.
VII.b)
Automatic sensor control
If one of the temperature sensors (CH, DHW) is damaged, an alarm sound is activated and the
display message informs about the failure; e.g.: 'CH sensor damaged'. The fan is disabled and
the pump is enabled regardless of the current temperature.
If the CH sensor is damaged, the alarm is active until a new sensor is installed. In the case of
DHW sensor damage, the alarm should be switched off by pressing MENU button – the controller
will restore operation with one pump (CH). A new sensor should be installed so that all modes of
CH boiler operation could be available.
VII.c)
Thermal protection of CH boiler (STB)
In a closed CH system, the controller is equipped with STB safety thermostat which protects the
CH boiler against an excessive temperature increase. When the temperature exceeds the pre-set
‘switch off’ value (default setting: 95
o
C), the contacts in the fan power supply circuit are opened.
The fan may be activated again only manually by pressing ‘reset’ button on the safety thermostat
casing after the sensor cools down.
VII.d)
Fuse
The regulator has a WT 6.3A tube fuse-link protecting the network.
Higher amperage fuse should not be used as it may damage the controller.
Summary of Contents for ST-979
Page 1: ...ST 979 user s manual 1...
Page 32: ...TECH 32...
